Ml 320 Cdi 2007 - unleaded petrol into diesel tank

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Fri 21 Nov 2014 22:23
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - johnwj

Honest John got away with 9l unleaded into a 60l diesel tank. What about 20.49 litres of BP Ult unleaded into a 95L ML tank. It was 3/4 full with diesel already and put in the unleaded, stopped when mistake recognized and topped to brim with 10.59l BP Ult derv. Internet says can add some engine oil as well....? how much would you say. So if i top up many times with Shell V power diesel at 3/4 full might I be OK?....how long should I do this for?......also should I add any other additives? Thanks.

Edited by johnwj on 21/11/2014 at 22:25

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Fri 21 Nov 2014 23:36
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - RobJP

You might be OK. Or might not. If it all goes wrong, it costs you (probably) thousands. Or you could get it into a garage, get the tank and system drained, and it might be less likely to go wrong.

You've got to decide on this one, I'm afraid. If it was my car, with that much petrol, then I'd probably not chance it.

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Sat 22 Nov 2014 10:24
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - Railroad.
Petrol in a diesel system is a problem, but don't believe what some people tell you that even so much as one drop of unleaded in your diesel fuel tank will leave you needing the entire fuel system replaced. If I were you I'd drain the tank completely and fill it right to the top with diesel. The chances are you'll be perfectly fine, but as the above poster says, it is your call.
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Sat 22 Nov 2014 11:58
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - Wackyracer
Petrol in a diesel system is a problem, but don't believe what some people tell you that even so much as one drop of unleaded in your diesel fuel tank will leave you needing the entire fuel system replaced. If I were you I'd drain the tank completely and fill it right to the top with diesel. The chances are you'll be perfectly fine, but as the above poster says, it is your call.

If that was the case, There would be many problems with diesel engines! Diesel and petrol in the fuel stations do have a bit of contamination as the tankers that deliver it are used for both and they never clean them inbetween changing fuels. The amount is likely to be a very tiny percentage though.

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Sat 22 Nov 2014 12:21
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - gordonbennet

Yes that would be a bit too much for my peace of mind too.

If twas mine i'd try a bit of clear reinforced hose (garden hose size) down the filler neck, it might be an easy siphoner at home, get as much out as possible, down to 1/4 tank or so and refill at the nearest garage.

I wouldn't sling the fuel, at that mix i'd chuck a gallon in every fill up, too much tax paid on that for dick turpin to fritter to waste it completely.

I'd also grab a bottle of Millers fuel additive, whatever it happens to be called this week, and add a double dose for the next few months.

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Sat 22 Nov 2014 14:53
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - madf

Add 2 liters of two stroke oil to the full tank.

Worked for me

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Mon 24 Nov 2014 08:55
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - MrEckerslikefromRamsbottom

That's the best bet to replace the lost lubricity. Two stroke oil from Morrisons. £2 for a 500ml bottle. I haven't found it cheaper anywhere else.

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Sat 22 Nov 2014 18:12
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - Cyd

The trouble is that the petrol breaks down the lubricity of the diesel and the more you drive it the more damage you do. The damage can take many 000's of miles to become catastrophic

There is a firm that does mobile fuel rescu, but sorry I don't know what they are called.

IIWY I'd have it drained and refill with diesel asap. Sell the contaminated stuff to someone with an oil boiler. You might get away with it then.

Of course, you might get away with it anyway. But the risk is up to you

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Sun 23 Nov 2014 23:07
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - johnwj

Thanks for all the comments. Drove it around all day sat and fine. Then added 14.02 L to the brim of shell diesel (unable to get V power locally). Did add approx 1.2 L of engine oil on the friday afternoon. Seems fine so far. Will have to decide whether to drain the tank fully I expect.....before trip to Truro mid week......

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Mon 24 Nov 2014 16:08
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - johnwj

Hi, I decided I could not bite the bullet any more and went online to find Fuel drainer (cover UK) and asked their oipinion as well. So we dicided to drain the tank. The local guy was 'fuel fixer' (franchise type) and James Elliot came out. Drained tank which took approx 2 hrs since was full having topped up with shell diesel and he left me with £10 worth of clean diesel so that I could go to shell and fill up with their diesel V-power. Cost to drain with some diesel £160 and cost of a full tank was £120 so in all cost me £280 for the error of sticking in 20L of unleaded...!!.....better than probable £5K that me MB dealer would have done to change everything. The ML is running fine and always has done from the initial error but now I hopefully have peace of mind as well......

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Mon 1 Dec 2014 16:12
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - johnwj

Well went down to Truro and back middle last week using shell V power. Approx 460 miles in total... Went like a dream and no problems at all. Diesel consumption 30-32 driving 70-80 .....just wonder if I would have been ok without the tank drain......we will never know.....!!

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Mon 1 Dec 2014 16:32
Ml 320 Cdi 2007 - unleaded petrol into diesel tank - RobJP

My wife managed to fill up a Nissan Navara with petrol a few years ago, didn't realise. About 3 miles later it conked out. The bill was in the region of £6k - fortunately, this was when these incidents were a bit more rare, and it was still covered by the insurance (thankfully).

I've known someone who did the same on a TDV8 Range Rover. The bill in that case was closer to £10k.

The £280 that it's cost you, I would describe as money well spent. If you hadn't, and if it went wrong, then you could well have been looking at the cost to fix being more than the value of the car.

Edited by RobJP on 01/12/2014 at 16:32

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